Method of making variegated hard surface coverings



Feb. 20, 1945. v SPENCER 2,369,866

I METHODVOF MAKING VARIEGATED HARD SURFACE COVERINGS 2 Sheets-Sheet 1 Filed Oct. 2, 1940 Feb. 20, 1945. V. SPENCER METHOD OF MAKING VARIEGATED HARD SURFACE COVERINGS Filed Oct. 2, 1940 2 Sheets-Sheet 2 Patented Feb. 20, 194

' METHOD OF MAKING VARIEGATED HARD SURFACE COVERINGS Virgil Spencer, East Petersburg, Pa, assignor to Armstrong Cork Company, Lancaster, Pa, a corporation of Pennsylvania Application October 2, 1940, Serial No. 359,828

Claims.

This invention relates to a method of making variegated hard surface covering and more.particularly to improvements in the method of making variegated linoleum by what is generally termed the cross-rolling process.

The cross-rolling process of making variegated linoleum as applied to the continuous production of linoleum on rotary inlaying machines of the Walton or Batten type contemplates the formation of a sheet having a definite directional graining commonly called jaspe, overlapping a plurality of such sheets and passing the overlapped sheets through a sheeting calender at right angles to the direction of graining thus forming an integral sheet and shortening and spreading the jaspe graining of the face of the sheet to obtain the desired variegation which is generally considered to resemble marble. It is known that graining produced by this process varies throughout the thickness of the sheet and that the graining of the back of the sheet bears only a remote resemblance to the graining on the face of the sheet.

One of the chief problems present in such practice resides in the visible discontinuity between sheets where an overlapped or overlapping sheet adheres to and becomes an integral portion of a following or preceding sheet. This phenomenon is termed hook-on in the industry and appears to be a visible distortion of face graining which is not compatible with the required variegation and presents an entirely difierent appearance at the sections where the overlapped sheets join one another. The cause of "hook-on is not known with any degree of certainty but it is believed to be due almost entirely to the abrupt change in volume of material present in the nip of the rolls at the overlapped portions of the sheet and the subsequent flow and surge of the plastic material resulting from increased pressure. It may be due in part to the fact that in some cases the edge portions of the overlapped sheets presented to the calender rolls turn over slightly when subjected to pressure and thus permit back graining to appear on the face of the sheet. In any event, this visible discontinuity is a seriousdistortion of face graining which is undesirable and which annually creates an enormous waste in the production of variegated linoleum on rotary inlaying machines.

The chief object of my invention is to provide improvements in method for making variegated hard surface covering by the cross-rolling process designed to eliminate substantially or entirely the as visible discontinuityprcsent in those portions of the finishedsheet where overlapped sections join. An object of my invention is to provide a method whereby a more satisfactory face variegation may be obtained in the cross-rolling process. A still further object is to obviate the abrupt change in volume of plastic composition at those places where one sheet joins and adheres to a second sheet in the-manufacture of variegated hard surface covering.

This invention relates to a method of making variegated hard surface coverings in which the steps comprise forming a vari-colored'mass of difierently colored granular compositions, subjecting said mass to pressure to form a sheet having a definite directional graining, skiving a portion of the under surface of said sheet so as to decrease the thickness of the sheet at the skived portion, overlapping similar sheets so that the skived portion of one sheet is disposed adjacent the face of a second sheet, and calendaring the overlapped sheets at an angle to the direction of graining to form a continuous sheet.

The attached drawings illustrate a preferred embodiment of my invention in which Figure l is a plan view of a device for making variegated hard surface covering by the crossroiling process;

Figure 2 is a view partly in elevation and partly in section of a portion of the device shown in Figure l, the frame of the device being removed to illustrate the skiving and edge forming mechanism; V

Figure 3 is an exaggerated plan view of a sheet severed into sections provided with an irregular sinuous edge;

Figure 4 is a view in elevation of the edge forming tool used in my process;

Figure 5 is a view in elevation of the skiving tool; and

Figure 6 isa sectional view of asheet of linoleum composition serving to illustrate the skived recess formed in its under surface.

Suitable mixing equipment is provided for forming two differently colored linoleum compositions. ment may be provided for any desired number of differently colored compositions. The difierently colored compositions are blended into a cohesive vari-colored mass which is fed to a tworoll sheeting calender '2 as shown in Figure 1. The face roll 3 of the calender 2 is maintained at a lower temperature than the back roll 4 in order to insure that a formed sheet will adhere thereto rather than to the back roll 4 and to It will be appreciated suitable equipassist in securing the desired graining. The roll 31s rotated at the same or a slightly greater speed than the roll 4 which extrudes the granules and elongates the difierently colored granules to some extent thus forming what is known as a jaspe sheet. provided to remove the jaspe sheet from the roll 3. Such equipment is well-known in the industry and does not require lengthly description for a full and complete understanding of my apparatus. and method. I have found it desirable in the substantial elimination of hook-on" to provide a recess or groove in the under surface of the formed jaspe sheet in order that, when a sheet is severed in sections, each section will be provided with a thin tapered edge of less thickneess than the body of the section. This, of course, materially reducesthe volume of plastic composition present in the nip of the cross-rolling calender at those points where overlapped sheets are joined. Such groove or recess is preferably provided in the center of the sheet as shown in Figure 6 but it will be understood it may be provided at any desired position in the sheet. If it is not desired to later sever the sheet in sections, such groove or recess may be formed at one edge of the sheet to insure such edge being of less thickness than the body of the sheet. For this purpose there is provided a skiving tool li (refer to Figure 2) which serves to skive or form a recess or groove 6 in a formed jaspe sheet 1.

The skiving tool 5 is preferably disposed adjacent the roll 3 in order that the roll 3 may serve as a platen therefor but it will be understood the tool 5 may be used to skive a groove in the sheet'l after it has been removed from the roll 3. In such case, a suitable backing plate or platen need be provided. The tool 5 skives a thin tapered ribbon from the sheet I leaving a tapered groove or recess therein. If desired to eliminate waste or scrap, such ribbon may'be fed again with the vari-colored mass to the rolls of the calender to form further portions of the sheet.

The skiving tool 5 preferably consists of a thin metal strip 8 having a sharpened and tapered edge 9 bent into the form shown in Figure 5. The tool 5 is bolted to a metal bar or rod ill held in a barrel H adjustably mounted upon a shaft i2 extending across the device. The skiving tool 5 need be adjustable with precision since the sheet I from which it skives a ribbon is usually quite thin. To adjust the skiving tool 5, there is provided a handwheel i3 secured to a threaded rod M which extends through the barrel H and into a threaded opening i5 provided in the bar ill. The bar I is keyed to the barrel ii to prevent its rotation. Rotation of the handwheel I 3 causes rotation of the threaded rod [4 permitting the bar In to be raised and lowered in the barrel I l to move the skiving tool toward and from the roll 3 thus varying the depth of the recess or groove skived in the formed sheet. It will be appreciated such adjusting mechanism permits grooves to be formed of any desired depth or even if desired the separation of the sheet in sections by completely cutting through the sheet.

It is desirable that the edge of the formed sheet which is disposed adjacent the face of the subsequent or preceding sheet be irregular in contour and have some portions thereof extending beyond the body of the sheet to a greater extent than other portions since this materially reduces the volume of plastic material present in the nip of the cross-rolling calender when overlapped sheets are joined and made into an integral sheet.

A doctor blade (not shown) is usuallyasoasoa have found that an irregular sinuous edge composed of a plurality of connected, undulated sigmoidal curves materially aids in reducing visible discontinuity. The term plurality of connected, undulated sigmoidal curves" is used herein to define a line formed of a plurality of connected curves which open in opposite directions and each of which has a wavy contour, as shown in Figure 3.

I provide a circular edge forming or severing tool l6 having its cutting surface formed of a plurality of connected sigmoidal curves of wavy contour (see Figure 4). Preferably, the tool it is likewise disposed adjacent the roll 3 in order that such roll may serve as a platen therefor and is supported by a lever l8 pivoted on a shaft 19 extending across the device. .The lower portion 20 of the lever i8 engages and is held in contact with a pin 2i held in a support 22. As the pin 2| is moved outwardly, it rotates the lever it about the shaft iii to move the severing tool it upwardly toward the roll 3. As the pin 2i is retracted within the support 22, the weight of the severing tool i6 is suflicient to rotate the lever l8 about the shaft thus moving the tool it in the opposite direction. The tool it is adjustable laterally of the shaft I8 in order that the sheet may be severed in sections of any desired width. Preferably, the cutter i6 is so disposed that the sheet 1 is severed in sections at the recessed portion so that each section terminates in an irregular tapered edge. Thus similar sections la and lb are produced each of which possesses a tapered irregular sinuous edge. The sections are placed on a conveyor 24 which carries them to a table 25 positioned adjacent the rolls of the cross-roiling calender 26. Such sections la and lb while trav eling on the conveyor are subdivided, either manually or mechanically, into suitable size to be fed to the cross-rolling calender 26.

The subdivided sheets are disposed in overlapping relation on the table 2-5 with the tapered irregular edge of one sheet disposed adjacent the face of the other sheet. As shown in Figure 1, the sections are fed to the cross-rolling calender face-down and accordingly the irregular edge of the sheet is the rear edge. Of course, if the continuous sheet 21 is to be formed face-up, the irregular edge would be that edge of the sheet first fed to the cross-rolling calender. The overlapped sheets are fed to the rolls of the crossrolling calender 26, at right angles to form a continuous integral sheet 21 and to further shorten and spread the graining to form variegations on the face thereof which resemble marble.

In operation, a cohesive vari-colored mass of linoleum composition is fed to the two-roll calender 2 and formed into a. sheet I having a. definite directional graining. While the sheet l adheres to the cold roll -3, the skiving tool 5 skives a portion of the under surface of such sheet so as to reduce its thickness, preferably at its central portion. The edge forming tool it then, while the sheet still adheres to the cold roll, severs the sheet at the skived portion thereof into two sections each of which is provided with a tapered, irregular sinuous edge composed of a plurality of connected, undulated sigmoidal curves. The sections are doctored from the cold roll 3 and placed upon a conveyor 24 which carries them to the cross-rolling calender 26. During their passage on the conveyor-24, the sections are subdivided, manually or mechanicalLv, into sheets of suitable size for feeding'to the crossrolling calender.

graining, removing The sheets are placed in overlapping relation 25 with the tapered irregular disposed adjacent the ,face of the other section and are fed to the rolls of the cross-rolling calender 26. As shownin Figure 1, such sheets are fed face-down so that the irregular edge is the rearward edge of the sheet. The sheets are cross-rolled to spread and shorten the graining and to form a continuous integral sheet which may be placed upon a suitable backing or ship on the table edge of one sheet to form a sheet havinga definite directional.

fed to the dies ofthe rotary inlaying machine as ping sections-so that cross-rolling process above described add little or nothing to the costs involved in making the sheet. The additional apparatus required in order to effectuate such improvements is inexpensive and does not require frequent replacement. Needless to say, however, the chief advantage of my improved process resides in the substantial or entire elimination of grain distortionat those sections of the continuous sheet where overlapped sheets are adhered to one another.

While I have described and illustrated a preferred embodiment of my invention, it will be understood my invention is not so limited since it maybe otherwise embodied or practiced within the scope of the following claims.

I claim:

- 1. In the method of making variegated hard steps comprising forming surface coverings, the V a vari-colored mass of differently coloredv granular compositions, subjecting said mass to pressure to form a sheet having a definite directional a portion of said sheet so as to form a portion of less thickness than the body of the-sheet extending in a direction parallel to the direction of graining, overlapping similar sheets so that the portion of less thickness of one sheet is disposed. adjacent the face of 2. second sheet, and calendering the overlapped sheets at an angle to the direction of graining to form a continuoussheet.

2. In the method of making variegated hard surface coverings, the steps comprising forming a vari-colored mass of diiIerently colored granular compositions, subjecting said mass to pressure to form a sheet having a definite directional graining,

severing a ribbon from the under surface of said sheet so as to decrease the thickness of the sheet at the severed portion thereof, overlapping similar sheets so that the portion of decreased thickness of one sheet is disposed adjacent the face of a second sheet, and calendering the overlapped sheets at an angle to the direction of graining to form a continuous sheet.

3. In the method of making variegated hard surface coverings, the steps comprising forming a vari-colored mass of differently colored granular compositions, subjecting said mass to pressure to form a sheet having a definite directional grain'ing, skiving a portion of the under surface of said sheet so as to decrease the thickness of the sheet at the skivedportion, overlapping similar sheets so that the skived portion of one sheet is dis'posed adjacent the face of a second sheet, and calendering the overlapped sheets at an angle to the direction of grainlng to form a continuous sheet.

4. In the method of making variegated hard surface coverings, the steps comprising forming a vari-colored mass of differently colored granular compositions, subjecting said mass to pressure graining, skiving a portion of the under surface of said sheet so as to decreasethe thickness of the sheet at the skived portion, separating said sheet at the skived portioninto sections, overlapthe skived portion at the edge of one section is disposed adjacent the face of another section, and calendering the overlapped sections at an angle to the direction of raining to form a continuous sheet.

5. In the method of making variegated hard surface coverings. the steps comprising forming a vari-colored massof differently colored granular compositions, subjecting said mass to pressure to form a sheet having a definite directional graining, skiving a portion of the under surface of said sheet so as to decrease the thickness of the sheet at the skived portion, severing said sheet into sections at the skived portion so as to form on each section an irregular tapered edge composed of a plurality of undulated sigmoidal curves, overlapping said sections so that the irregular tapered edge of one section is disposed adjacent the face of the other section, and calendering the overlapped sections at an angle to the direction of graining to form a continuous sheet.

6. In the method of making variegated hard surface coverings, the steps comprising forming a vari-colored mass of differently colored granular compositions, subjecting said mass to pressure to form a sheet having a definite directional graining, skiving a portion of the under surface of said sheet so as to decrease the thickness of the sheet at-the skived portion, severing said sheet into sections at the skived portion so as to form on each section an irregular tapered edge composed of a plurality of connected undulated sigmoidal curves, subdividing said sections into sheets of predetermined size so that an edge of each sheet is formed from the irregular edge of the section, overlapping said subdivided sheets so that the irregular edge of one sheet is disposed adjacent the face of a second sheet, and calendering the overlapped sections at an angle to the direction of graining to form a continuous sheet. '7. In the method of forming a variegated sheet of hard surface covering by a cross-rolling operation, the steps which comprise forming a plurality of similar sheets each having a skived edge, overlapping said sheets so that the skived edge of one sheet is disposed adjacent the face of a second sheet, and cross-rolling said sheets to form a continuous sheet.

8. In the method of making variegated hard surface covering, the steps comprising forming a cohesive'vari-colored mass of differently colored granular compositions into a sheet having a definite directional graining, severing said sheet into sections while simultaneously forming a sinuous edge having a plurality of sigmoidal curves impressed thereon, disposing a plurality of similar sections in overlapping relationship with the section adjacent the face of a second section, and calendaring the overlapped sections at an angle to the direction of graining to form a continuous integral sheet.

9. In the method of making variegated hard suri'ace covering, the steps comprising i'orining a cohesive vari-colored mass 01' diil'erently colored granular compositions into a sheet having a deflnite directional graining and an irregularedge composed of a plurality of undulated, sigmoidal curves, disposing a plurality otisaid sheets in overlapping relationship with the irregular edge 01' one sheet adjacent the face 01' a second sheet, and calendering the overlapped sheets at an angle to the direction 01' graining to form a continuous integral sheet. l r

10. In the method of making variegated hard surface covering, the steps comprising forming in overlapping relationship with the irregular edge of one section adjacent the face oi! a second,

section, and calendering the overlapped sections at an angle to the direction of graining to form a continuous integral sheet.

VIRGIL SPENCER. 

